UPDATE: Inscription kites are trainable and require skill level of at least 600.
The new MoP craftable pets were originally BoP, but they've been updated to Bind on Use. This is great news for players who don't have toons with the Engineering, JC, or Inscription professions! Now they won't have to power level these three professions just to get the pets. ;)
Although the companions themselves are BoU, the designs that teach players how to make the JC pets are still BoP. The Engineering schematic is BoU.
As for Inscription, it's not clear yet if the craftable kite pets from this profession will be trainable or require an actual recipe.
Where will these recipes come from? I have yet to find the source of the Engineering schematic. Since it's BoU, it could be a random world drop. Or maybe a limited item from a vendor. Well, I can only hope that I'll get lucky enough to either loot this recipe or find a superb deal for it on the AH. I probably shouldn't hold my breath, though. :P
According to a Wowhead comment, the designs for the JC pets might come from the Golden Lotus faction dailies that are unlocked at level 90 in the Vale of Eternal Blossoms. These dailies reward Treasures of the Vale, and the pet designs might drop from it.
Since both of these recipes are BoP, it's likely that you'll have to be a JC yourself to be able to loot and/or see them drop in the reward bag.
If this is the case, I guess I know which toon I'll be leveling after my druid main - my priest who happens to be a Jewelcrafter. All for two pets, lol! Or perhaps I can coax a JC guildmate of mine to do these dalies with me in hopes that the designs will drop for him so he can craft the pets for me. >:P